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 A294124 Numbers k such that (13*10^k + 179)/3 is prime. 0
 1, 5, 8, 21, 37, 61, 62, 126, 188, 221, 253, 523, 654, 1875, 2372, 2394, 3073, 4158, 6663, 6881, 167911 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS For k>1, numbers such that the digit 4 followed by k-2 occurrences of the digit 3 followed by the digits 93 is prime (see Example section). a(22) > 2*10^5. LINKS Makoto Kamada, Factorization of near-repdigit-related numbers. Makoto Kamada, Search for 43w93 EXAMPLE 5 is in this sequence because (13*10^5 + 179)/3 = 433393 is prime. Initial terms and primes associated: a(1) = 1, 103; a(2) = 5, 433393; a(3) = 8, 433333393; a(4) = 21, 4333333333333333333393; a(5) = 37, 43333333333333333333333333333333333393; etc. MATHEMATICA Select[Range[0, 100000], PrimeQ[(13*10^# + 179)/3] &] (* corrected by Georg Fischer, Jul 22 2019 *) CROSSREFS Cf. A056654, A268448, A269303, A270339, A270613, A270831, A270890, A270929, A271269. Sequence in context: A138810 A331700 A105634 * A120036 A036381 A277369 Adjacent sequences:  A294121 A294122 A294123 * A294125 A294126 A294127 KEYWORD nonn,more,hard AUTHOR Robert Price, Oct 23 2017 EXTENSIONS a(21) from Robert Price, Nov 17 2018 STATUS approved

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Last modified January 16 09:13 EST 2021. Contains 340204 sequences. (Running on oeis4.)